Device for preventing axial movement

ABSTRACT

A device for preventing axial movement of an elongated member ( 1 ) applied through the skin of a mammal at a puncturing position has a plaster ( 2 ) designed to cover the surface around the puncturing position and having at least an adhesive layer ( 4 ) for securing it to the skin as well as an opening ( 9 ) through the layer thereof for the passage of said elongated member therethrough. The device also has a clamp ( 8 ) secured to plaster and adapted to clamp around the elongated member when the elongated member is applied to the skin and the plaster is applied on the surface around said puncturing position. The clamp is thin and substantially flat.

BACKGROUND OF THE INVENTION AND PRIOR ART

The present invention generally relates to a device for preventing axialmovement of any elongated member applied through the skin of a mammal ata puncturing position. Accordingly, the purpose of such a device is tokeep said elongated member applied through the skin of a mammal fordifferent reasons. Such an elongated member is mostly stiff and sharp,so that it may be pearced through the skin of said mammal, normally ahuman being, but it may also be flexible, such as a catheter, which hasbeen pearced through the skin by using a cannula needle thereafterretracted.

More specifically, the invention relates to such a device comprising aplaster designed to cover the surface around the puncturing position andhaving at least an adhesive layer for securing it to the skin as well asan opening through the layer(-s) thereof for the passage of saidelongated member therethrough. The plaster is used for securing theneedle on the skin. By this the patient also has a visible securityagainst the needle falling out.

A device of this type may for instance be used for preventing axialmovement of a cannula needle when carrying out hemo-dialysis, in whichthe blood of a patient suffering from impaired kidney function isconducted from a patient blood vessel to a dialysis machine and isreturned to the patient after treatment. In such a case two cannulaneedles may be used, one for draining blood from the patient and theother for returning the treated blood thereto. It is in this case ofvital importance that a said device is extremely reliable, since itwould of course be a catastrophe if the cannula needle returning theblood to the patient would move out of the correct position, so thatblood would only be drained from the body of the patient without beingreturned. However, in this case also a single needle may be used. When asingle needle is used, the blood is received from the patient andtransferred back to the patient through the same needle. The needle is,in its turn, connected to a tube that is split up into two parts, onefor venous blood and one for arterial blood.

Devices of this type are disclosed in for example DE 3105187, DE19508073 and U.S. Pat. No. 5,087,248. These devices use the material ofthe plaster for keeping the cannula needle, catheter or the like inposition. However, this material may be stretched or partially tornapart would the patient move, so that there is a risk that the elongatedmember moves axially. These devices also use an adhesive to keep theelongated member in place by securing wings attached to the elongatedmember to the skin, so that it is important that this adhesive bindsstrongly enough to said wings. In the case of a cannula needle, this isvery thin, so it is necessary to apply an adhesive tape or the like onwings provided extra therefor at a remarkable distance from the needleportions penetrating the skin.

A device according to the preamble of appended claim 1 is known throughWO 97/21459. The clamping means used for keeping the needle in place israther complicated to the construction and is not able to hold theneedle as firm as desired in some situations.

Furthermore, it may be mentioned that U.S. Pat. No. 6,231,548 and U.S.Pat. No. 5,084,026 disclose devices of another type differing from thepresent invention by the fact that the plaster thereof is not penetratedby the elongated member, so that the plaster does not cover the surfacearound the puncturing position of the elongated member. A plaster isthere instead used to be carried for other means holding the elongatedmember in place. The devices are rather complex, secure the elongatedmember at a considerable distance from the puncturing position and donot use the plaster to cover the surface around the puncturing position.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a device of the typedefined, improving the operation reliability and accuracy with respectto such devices already known.

This object is according to the invention obtained by providing such adevice with a clamping means being thin and substantially flat andprovided with a lateral opening for laterally introducing a saidelongated member between clamping portions thereof, and said clampingmeans including parts of substantially rigid material provided withclamping portions adapted to bear against a said elongated member.

It is by this construction of the clamping means possible to clamp closeto the penetration point of the elongated member thereby minimizing anylever action thereon, so that the elongated member, such as a needle,may be held very firmly and reliably against axial movement thereofwithout the use of any adhesive strips, glue or the like. It is alsocomfortable to the patient if the device can be kept as this aspossible.

“Clamp ”should be interpreted as bearing on the elongated member undertension from at least two different directions through members, whichwould move closer to each other would not the elongated member belocated therebetween. This is quite different than having an adhesivetape or a plaster portion secured to the elongated member therearoundwhile only relying on the adhesive for preventing said axial movement ofthe elongated member.

According to an embodiment of the present invention said clamping meansis of (a) material(-s) being substantially more rigid than thematerial(-s) forming the plaster, which facilitates the obtention of theclamping function thereof.

According to another embodiment of the invention surfaces through whichthe clamping portions are adapted to bear against a said elongatedmember are made of a substantially rigid material. This enables saidclamping portions to efficiently engage circumferential surfaces of theelongated member, such as a cannula needle for firmly holding thiselongated member in place through the clamping action.

According to another embodiment of the present invention said clampingmeans has clamping portions with sharp gripping edges adapted to bearagainst a said elongated member clamped thereby. This further increasesthe reliability of the gripping action of the clamping means.

The elongated member may for example be made of metal.

According to another embodiment of the present invention said plaster isprovided with a pocket formed between two adjacent layers thereof andhousing said clamping means, so that the clamping means will be anintegral part of the plaster.

According to another embodiment of the present invention said clampingmeans is transferable between an inactive state allowing a saidelongated member to be introduced between clamping portions thereof andan active state in which said clamping portions bear under tensionagainst a said elongated member. This means that the elongated membermay without any problems be introduced into the clamping means, but thismay nevertheless efficiently clamp the elongated member when desired bytransferring the clamping means to said active state.

According to another embodiment of the present invention constituting afurther development of the embodiment last mentioned at least saidclamping portions of said clamping means are made of a material having ahigh coefficient of thermal expansion in the region around the bodytemperature of a mammal for which the device is intended to be used suchas to be influenced by the temperature when applied together with aplaster on the skin of a said mammal for being transferred from saidinactive to said active state through the temperature rise causedthrough heat transfer from the body of said mammal. This way ofrealising the clamping means is very simple and results at the same timein a reliable function thereof. In this case at least said clampingportions of said clamping means may be made of a so-called memory metal.

According to another embodiment of the present invention said clampingmeans comprises at least one spring member connected to said clampingportions for urging them towards each other. One or more spring membersmay in this way be used for obtaining a reliable clamping action of theclamping means. “Spring member” is here to be interpreted very broadlyand comprises all types of members acting as a spring by trying to lowerthe potential energy thereof by changing shape.

According to another embodiment of the present invention associated withthe embodiment last mentioned the device comprises a blocking memberadapted to hold the clamping portions apart in said inactive state forallowing introduction of a said elongated member therebetween and whenreleased allowing said spring member to transfer the clamping means tothe active state, so that such a spring member may be used toefficiently clamp an elongated member without making it difficult tointroduce the elongated member into the clamping means.

According to another embodiment of the present invention the devicecomprises an elongated flexible, preferably adjustable, such as by beingelastic, band-like member secured to the plaster and adapted to beapplied around a body part of a mammal on which a said puncturingposition has been applied for assisting the adhesive layer of theplaster in holding the plaster secured around the puncturing position,so that the holding of the plaster and by that the clamping means inplace is further improved.

Further features of the present invention appear from the followingdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a specificdescription of various embodiments of the present invention cited asexamples.

In the drawings:

FIG. 1 is a schematic perspective view illustrating a typical use of adevice according to the present invention,

FIG. 2 is a partially sectioned perspective view illustrating thegeneral construction of a device according to the present invention,

FIG. 3 schematically illustrated a clamping means according to anembodiment of the present invention,

FIG. 4 schematically illustrates a clamping means according to anotherembodiment of the present invention, and

FIGS. 5-7 schematically illustrate clamping means including at least onespring member according to other embodiments of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 schematically illustrates the use of a device according to thepresent invention for preventing axial movement of en elongated memberin the form of a cannula needle 1 applied through the skin of an arm ofa human for draining blood from a vein or supplying a fluid, preferablyblood, but possibly also for instance anaesthetic thereinto. It isstressed that the most critical thing is to return blood to the patient.The cannula needle is passing through a plaster 2 being secured to theskin by an adhesive layer thereon and further secured to the arm of apatient by a band 3 secured to the plaster and applied around the armwhile forming a loop through using for instance a hook- andloop-fastener. The band 3 is preferably adjustable, possibly by beingelastic for adapting it to the body of the patient and efficientlyassisting the adhesive layer of the plaster in holding the plaster inplace without causing inconveniences to the patient. The cannula needle1 is in fact firstly put in place and thereafter the plaster 2 isarranged over the puncturing position.

FIG. 2 illustrates the principal construction of a device according tothe present invention. The plaster 2 has an adhesive layer 4 forsecuring it to the skin, a carrier layer 5 on top thereon and anuppermost force absorbing coating layer 6, preferably made ofconventional plaster fabric material. A pocket 7 is formed between thecarrier layer and the coating layer 6 for housing a clamping means 8made of a material being substantially more rigid than the materialforming the plaster. The material of the clamping means may for instancebe metal or hard plastic. Different parts of the clamping means may alsobe made of different materials.

The plaster has a lateral slot 9 and the clamping means has a lateralslot 10 for introducing an elongated member into the opening of theplaster and between clamping portions 11, 12 of the clamping means,respectively. Accordingly, the elongated member is firstly appliedthrough the skin at a puncturing position, so that this puncturingposition is perfectly visible when applying the elongated member, suchas a cannula needle. The plaster is then moved laterally with respect tothe elongated member so that this is introduced into the slots 9 and 10to the position shown in FIG. 2, whereupon the adhesive layer of theplaster is pressed against the surface of the skin surrounding thepuncturing position. If the elongated member is not appliedperpendicularly to the skin surface the plaster is applied with theslots 9, 10 so that the inclined elongated member when seen in adirection perpendicular to the plaster surface will extend in thedirection of the slots. This means that the clamping portions formingopposite surfaces of the slot 10 of the clamping means will not try topivot the elongated member when clamping it. Thus, the elongated memberis clamped through parts of rigid material provided with clampingportions 11, 12 adapted to bear against the elongated member and actingthereupon substantially in a plane in parallel with the surface of theskin upon which the plaster is arranged. Furthermore, the elongatedmember is intended to extend through the clamping means between theclamping portions thereof while making a large angle with the plaster,preferably extending substantially perpendicularly thereto.

FIG. 3 and. FIG. 4 illustrate two possible constructions of the clampingmeans. These are thin and disc-like members made of a memory metalhaving a high coefficient of thermal expansion in the region around thebody temperature of a mammal, mostly a human, for which the device isintended to be used such as to be influenced by the temperature whenapplied together with the plaster on the skin of a said mammal for beingtransferred from an inactive state shown for the embodiment in FIG. 3allowing the introduction of an elongated member between the clampingportions 11, 12 or claws thereof to an active state, in which theclamping portions clamp around an elongated member, as shown for theembodiment according to FIG. 4, through the temperature rise causedthrough heat transfer from the body of the human.

FIG. 5 illustrates how the clamping means may comprise a spring member13 connected to the clamping portions 11, 12 for urging them towardseach other. It is also schematically illustrated through dashed lineshow the device may comprise a blocking member 14 adapted to hold theclamping portions apart in an inactive state of the clamping means forallowing introduction of an elongated member therebetween and whenreleased, here displaced, allowing the spring member 13 to transfer theclamping means to the active state while urging the clamping portions11, 12 towards each other. This blocking member has preferably areversable function, e.g. it is then possible to re-enter the blockingmember in order to be able to release the needle from its clampposition.

FIG. 6 illustrates a clamping means having three rings 15-17 with outersharp edges pressed against each other through a spring band 18 havingan opening 19, through which an elongated member may be introducedlaterally between the rings while pressing them apart. Once theelongated member is introduced between the rings the spring band 18 willurge the clamping portions formed by the outer ring surfaces with theedges towards each other for firmly clamping the elongated member.

FIG. 7 illustrates a further possible embodiment of a clamping means tobe secured to a plaster in a device according to the present invention.This clamping means has two plates 20, 21 with lateral slots 22, 23 forbeing laterally moved into engagement with an elongated member. Springmembers 24, 25 are associated with the respective plate for trying tomove them apart while clamping an elongated member introduced into theslots 22, 23 through bottom surfaces 26, 27 thereof. In this case ablocking member in the form of for instance a thread (not shown) to becut off for the transfer from the inactive to the active state of theclamping means may be applied. This embodiment may be slightly modifiedfor using compressive forces instead of tension forces. The bottomsurfaces would then be oppositely directed and the spring members 24, 25replaced by compressive springs or other compressive means pressing theplates towards each other.

The invention is of course not in any way restricted to the embodimentsdisclosed but may be varied and modified within the scope of theappended claims.

The elongated member may be provided with intended irregularities over aportion thereof for improving the grip of the clamping means on theelongated member.

1. A device for preventing axial movement of an elongated member (1),such as a cannula needle, applied through the skin of a mammal at apuncturing position, said device comprising a plaster (2) structured andarranged to cover a surface around the puncturing position and having atleast an adhesive layer (4) for securing to the skin and an opening (9)through the layer (4) thereof for the passage of said elongated member(1) therethrough, the device further comprising means (8) secured to theplaster (2) and structured and arranged to clamp around said elongatedmember (1) when the elongated member (1) is applied through the skin ofa mammal and the plaster (2) is applied on the surface around saidpuncturing position, wherein said clamping means (8) is thin andsubstantially flat and provided with a lateral opening (10) forlaterally introducing said elongated member (1) between clampingportions (11, 12) thereof, and said clamping means (8) includes parts ofsubstantially rigid material provided with said clamping portions (11,12) which are structured and arranged to bias from at least twodifferent directions against said elongated member (1).
 2. A deviceaccording to claim 1, wherein said clamping means (8) is made ofmaterial being substantially more rigid than the material forming theplaster (2).
 3. A device according to claim 1, wherein surfaces throughwhich the clamping portions (11, 12) are structured and arranged to bearagainst a said elongated member are made of a substantially rigidmaterial.
 4. A device according to claim 1, wherein said clamping means(8) has clamping portions (11, 12) with sharp gripping edges structuredand arranged to bear against a said elongated member clamped thereby. 5.A device according to claim 1, wherein said clamping means (8) is madeof metal.
 6. A device according to claim 1, wherein said plaster (2) isprovided with a pocket (7) formed between two adjacent layers (5, 6)thereof and housing said clamping means (8).
 7. A device according toclaim 6, wherein said plaster (2) comprises at least two additionallayers (5, 6) besides said adhesive layer (4), and said pocket (7) isformed between two such additional layers (5, 6).
 8. A device accordingto claim 7, wherein the plaster (2) comprises a carrier layer (5)arranged on top of the adhesive layer (4) and an uppermost coating layer(6), and said pocket (7) is formed between said carrier layer andcoating layer (6).
 9. A device according to claim 1, wherein saidclamping means (8) is transferrable between an inactive state allowingsaid elongated member (1) to be introduced between clamping portions(11, 12) thereof and an active state in which said clamping portions(11, 12) bias against said elongated member (1).
 10. A device accordingto claim 9, wherein at least said clamping portions (11, 12) of saidclamping means are made of a material having a high coefficient ofthermal expansion in the region around body temperature of the mammalfor which the device is used and structured and arranged to beinfluenced by the temperature when applied together with the plaster (2)on skin of said mammal for being transferred from said inactive to saidactive state through the temperature rise caused through heat transferfrom the body of said mammal.
 11. A device according to claim 10,wherein at least said clamping portions (11, 12) of said clamping meansare made of a memory metal.
 12. A device according to claim 9, whereinsaid clamping means (8) comprises at least one spring member (13, 18,24, 25) connected to said clamping portions (11, 12) for urging themtowards each other.
 13. A device according to claim 12, additionallycomprising a blocking member (14) strucuted and arranged to hold theclamping portions (11, 12) apart in said inactive state for allowingintroduction of said elongated member (1) therebetween and, whenreleased, allowing said spring member (13, 18, 24, 25) to bias theclamping means (8) to the active state.
 14. A device according to claim1, wherein said plaster opening (9) is formed by a lateral slot into theplaster (2) for enabling introduction of said elongated member (1) intosaid opening (9) after the elongated member (1) has been applied throughthe skin of the mammal.
 15. A device according to claim 1, additionallycomprising an elongated flexible, preferably adjustable, such as bybeing elastic, band-like member (3) secured to the plaster (2) andstructure and arranged to be applied around a body part of the mammal onwhich said puncturing position has been applied for assisting theadhesive layer (4) of the plaster (2) in holding the plaster (2) securedaround the puncturing position.
 16. A device for preventing axialmovement of an elongated member (1), such as a cannula needle, appliedthrough the skin of a mammal at a puncturing position, said devicecomprising a plaster (2) structured and arranged to cover a surfacearound the puncturing position and having at least an adhesive layer (4)for securing to the skin and an opening (9) through the layer (4)thereof for the passage of said elongated member (1) therethrough, thedevice further comprising means (8) secured to the plaster (2) andstructured and arranged to clamp around said elongated member (1) whenthe elongated member (1) is applied through the skin of a mammal and theplaster (2) is applied on the surface around said puncturing position,said clamping means (8) is thin and substantially flat and includesparts of substantially rigid material provided with clamping portions(11, 12) structured and arranged to bear against said elongated member(1), wherein said clamping means (8) and plaster (2) are provided with alateral slot-formed opening (9,10) structured and arranged for laterallyintroducing said elongated member (1) between clamping portions (11, 12)of said clamping means (8) by moving the plaster (2) with said clampingmeans (8) laterally with respect to said elongated member (1) appliedthrough the skin, and said clamping portions (11, 12) are structured andarranged to bear against said elongated member (1) while actingthereupon substantially in a plane in parallel with the surface of theskin upon which the plaster (2) is arranged.
 17. A device according toclaim 16, wherein said clamping means (8) is structured and arranged toclamp said elongated member (1) extending through said clamping means(8) between said clamping portions (11, 12) at a large angle withrespect to said plaster (2).
 18. A device according to claim 17, whereinsaid large angle is about 90°.
 19. A device according to claim 16,wherein said clamping portions (11, 12) are structured and arranged tobias from at least two different directions against said elongatedmember (1).
 20. A device according to claim 16, wherein said clampingmeans (8) is transferrable between an inactive state allowing saidelongated member (1) to be introduced between clamping portions (11, 12)thereof and an active state in which said clamping portions (11, 12)bias against said elongated member (1).